ViewState Vs Data Caching

http://www.codersource.net/asp_net_viewstate_versus_data_caching.aspx

Data Caching is the keeping of frequently used data in memory(RAM) for ready access by your ASP.NET. (Mostly used with frequent database access of huge number of records while paging)

Whereas Viewstate stores the page's controls data in hidden field in the page itself. ViewState also provides a StateBag, which is a special collection or dictionary, for each page that you can use to store any object or value, associated with a key, to retain across PostBacks. ViewState is by default serialized and passed across page PostBacks as a hidden form field, __VIEWSTATE, that is Base64 encoded so that it is not easily readable, but not encrypted.